Clinical audit of the use of renal biopsy in the management of isolated microscopic hematuria.

Whether renal biopsies are indicated for the investigation of microscopic hematuria is a subject of debate. In this retrospective study we evaluated our use of renal biopsy in patients who presented between 1985 and 1995 with microscopic hematuria but without proteinuria, hypertension or renal insufficiency. Of 111 patients, 75 had a renal biopsy. Histological diagnoses included thin membrane nephropathy (TMN) (36%), IgA nephropathy (IgAN) (23%), non-IgA mesangioproliferative glomerulonephritis (MPGN) (9%), mild glomerular abnormalities (11%), focal global glomerulosclerosis (FGS) (4%) and normal (17%). After 85 patients had been followed for a mean of 43 months there were no deaths, 3 patients had proteinuria (IgAN 2, no biopsy 1), 1 had proteinuria and renal insufficiency (immune negative MPGN) and 11 were hypertensive (TMN 3, IgAN 2, normal 2, FGS 1, no biopsy 3). Hematuria resolved in 23 patients. Only 11 patients were still attending the nephrology clinic and 27% of the patients who were advised to continue annual follow-up with family doctors had not done so. In summary, the information obtained from renal biopsy rarely altered clinical management. Hypertension developed in 13% of the patients followed but it was not predicted by the biopsy result. Although a renal biopsy will usually be diagnostic it is difficult to justify in patients who have isolated microscopic hematuria.